Utilities including; underground water lines, gas lines, air pressurized telephone cables, pressurized vessels or any apparatus where containment is a consideration, can develop leaks.
Unfortunately, there are times when the containment is penetrated, either by chemical degradation (electrolysis), mechanical stresses, or similar phenomena. These penetrations cause leaks in the system and permit water to seep inside or the systems contents to leak out.
Discovering and repairing this damage can cost the provider substantial sums of money. One of the reasons is that it is sometimes necessary to excavate in several points. Another reason is that it might be necessary to unearth hundreds of yards of an underground system due to the impossibility of identifying the exact location of the leak.
There have been a number of techniques used to aid the provider in more accurately pinpointing the area of breakage. One technique that has enjoyed a period of success is the technique of obtaining a preliminary rough location of the leak by taking pressure measurements along the system and calculating the leaks position based on pressure changes. However, the problem with this technique is the range of detection, which can be anywhere from 300 feet to 6,000 feet.
Another technique is to incorporate the above prior art and in addition introduce a detectable tracer gas into the containment system. The tracer gas (like helium or hydrogen) mixes with the contents of the system with a natural or induced flow. The tracer gas escapes the containment through the leak and rapidly rises upwardly and becomes detectable outside the containment or at the surface of the ground if buried. A mass spectrometer is then used to detect the tracer gas. The problem with the spectrometers is that their operation depends upon separation of the tracer gas in a vacuum by imparting an electrical charge to the gas sample containing the tracer gas. The sample is pushed through a magnetic field, and the ions collected from the results. The electronics in such a device include a supply of high voltage and the vacuum system. All of these components tend to make the mass spectrometer bulky, complicated and expensive. With this type of equipment, it is difficult to operate in areas where access to such heavy equipment can be difficult.
An additional problem with the prior art was the ability to accurately detect the tracer gas. In many of the prior art devices, other non-tracer gases had the ability to set-off the detector in a manner undistinguishable from the tracer gas, hence, causing false readings.
An additional problem with the prior art is the affect that humidity has upon the accuracy of the detection of the tracer gas. Increased humidity decreases the ability of the sensor to detect the tracer gas in low concentrations.
Accordingly, it is desirable to provide a lightweight detector that can more accurately detect a tracer gas, and not produce false readings in the presence of non-tracer gas or elevated humidity.